Note 7 - Stockholders' Equity - Stock Options Activity (Details) - USD ($)	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Outstanding, beginning balance (in shares)	4,225,537	4,413,870
Outstanding, weighted-average exercise price, beginning balance (in dollars per share)	$ 1.45	$ 1.88
Outstanding, weighted-average exercise price, ending balance (in dollars per share)	$ 1.42	$ 1.45	$ 1.88
Outstanding, weighted-average remaining contractual life (Year)	2 years 328 days	4 years 36 days	4 years 36 days
Outstanding, aggregate intrinsic value	$ 176,575	$ 158,675	$ 398,250
Granted, options (in shares)	319,500	100,000
Granted, weighted-average exercise price (in dollars per share)	$ 0.97	$ 0.92
Expired, options (in shares)		(288,333)
Expired, weighted-average exercise price (in dollars per share)		$ 2.90
Outstanding, ending balance (in shares)	4,545,037	4,225,537	4,413,870
Exercisable, options (in shares)	4,520,037
Exercisable, weighted-average exercise price (in dollars per share)	$ 1.42
Exercisable, weighted-average remaining contractual life (Year)	2 years 328 days
Exercisable, aggregate intrinsic value	$ 176,575